code: def _testRingAllReduce(self, num_workers, num_gpus, shape, subdiv):
      start_time = time.time()
      build_f = self._buildRing(num_workers, num_gpus, subdiv)
      self._testAllReduce(num_workers, num_gpus, shape, build_f)
      elapsed = time.time() - start_time
      tf_logging.info(
          "RingAllReduce num_workers=%d num_gpus=%d shape=%s "
          "subdiv=%d elapsed=%f"
          % (num_workers, num_gpus, shape, subdiv, elapsed)
      )
  
imports: import time
  import numpy
  from tensorflow.core.framework import types_pb2
  from tensorflow.python.distribute.v1 import all_reduce
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import ops
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import state_ops
  from tensorflow.python.platform import test
  from tensorflow.python.platform import tf_logging
label_desc: Use image node_id 8 for calling the AllReduceTest obj's underlying member method code with example usage: obj._testRingAllReduce(num_workers, num_gpus, shape, subdiv) without return types